What would make radiator fan not to come on?
The radiator fan is a crucial component of your vehicle's cooling system, designed to prevent the engine from overheating by drawing air through the radiator. When the fan fails to operate, it can lead to engine overheating and potentially costly repairs. In this article, we’ll explore the common reasons why a radiator fan might not come on and what you can do to address the issue.
1. Blown Fuse
The radiator fan is powered by an electrical circuit, and like any electrical component, it relies on a fuse to protect it from power surges. If the fuse is blown, the fan will not receive power and won’t turn on. Checking and replacing a blown fuse is often a simple fix.
2. Faulty Fan Relay
The fan relay acts as a switch that controls the power supply to the radiator fan. If the relay is defective, it can prevent the fan from operating. A professional mechanic can test the relay and replace it if necessary.
3. Malfunctioning Temperature Sensor
The radiator fan is triggered by the engine's temperature sensor, which monitors the coolant temperature. If the sensor is faulty, it may fail to signal the fan to turn on, even when the engine is overheating. Replacing the temperature sensor can resolve this issue.
4. Wiring Issues
Damaged or corroded wiring can disrupt the electrical connection to the radiator fan. Inspecting the wiring for visible damage or loose connections is essential. Repairing or replacing damaged wires can restore the fan's functionality.
5. Failed Radiator Fan Motor
Over time, the motor that powers the radiator fan can wear out or fail completely. If the motor is the culprit, the fan will need to be replaced. This is a more involved repair but is necessary to maintain proper engine cooling.
6. Faulty Control Module
Modern vehicles often use a control module to manage the operation of the radiator fan. If the module malfunctions, it may not send the correct signals to the fan, preventing it from turning on. Diagnosing and replacing a faulty control module typically requires specialized equipment.
7. Low Coolant Levels
In some cases, low coolant levels can prevent the temperature sensor from accurately detecting the engine's heat, which may result in the fan not being activated. Ensuring the coolant is at the proper level can help avoid this issue.
Steps to Diagnose the Problem
If your radiator fan isn’t coming on, follow these steps to diagnose the issue:
- Check the fuse box for a blown fuse and replace it if necessary.
- Inspect the fan relay and replace it if it’s faulty.
- Test the temperature sensor to ensure it’s functioning correctly.
- Examine the wiring for damage or loose connections.
- Manually test the fan motor by applying power directly to it.
- Consult a professional mechanic if the issue persists.
Conclusion
A radiator fan that doesn’t come on can lead to serious engine problems if not addressed promptly. By understanding the potential causes and taking the appropriate steps to diagnose and fix the issue, you can keep your vehicle running smoothly and avoid costly repairs. If you’re unsure about any of these steps, don’t hesitate to bring your car to a trusted auto repair shop like Kevin’s Autos for professional assistance.
Frequently Asked Questions
What tells the radiator fan to turn on?
The engine temperature should trigger the fan to turn on. It will also turn the fan off once the engine has cooled to under 200 degrees. You may have heard of a part called the radiator fan switch or temperature fan switch. This is linked to a thermostat and works much like your home's HVAC system.
How do I know if my radiator fan resistor is bad?
What common symptoms indicate you may need to replace the Cooling Fan Resistor?
- Cooling fan never stops running even with the ignition off.
- Cooling fan never kicks in and engine temperature increases abnormally.
Can a bad thermostat cause the radiator fan not to come on?
The thermostat acts as the control center for your HVAC system, including the fan. If the thermostat is faulty, it may not send the proper signals to the fan, preventing it from turning on or functioning at the desired speed.
How do I know if my radiator fan relay is bad?
If the cooling fan relay has failed, you may see warnings, such as the check engine light and the temperature warning light, pop up on the dash, but first, you may notice that the A/C stops cooling. More about that in the next paragraph. The check engine light illuminating may indicate a faulty cooling fan relay.
Why is my radiator fan not turning on?
A faulty fan motor can result in the radiator fan not running when the AC is on (2). Fuse or relay issue: A blown fuse in the fan circuit or a faulty relay can disrupt the power supply to the radiator fan, causing it to fail to turn on. Checking the fan fuse and relay is an essential step in diagnosing the problem (2).
Does a fuse control radiator fan?
Which fuse will rotate radiator fans in a car? On the inside of your fuse box (your car may have more than one) there should be a fuse location marked AUX FAN. This would be for electrical fans that cool the motor over a certain temperature.
Can a bad temperature sensor cause a fan not working?
A signal from the coolant temperature sensor is what triggers the ECU to turn on the radiator fan, and if it's faulty, it can prevent the fan from working at all. Test the fan relay. Since the relay operates as a switch for the fan's power, a defective cooling fan relay won't energize the circuit.
Why is my radiator fan not kicking on?
Overheating can damage the radiator fan, wiring, or the fan motor. 2. Check the Coolant Level Low or no coolant can cause the fan to not turn on because some cars have a temperature sensor that only works when coolant is present.
How do I test if my radiator fan is working?
There are a few ways to test the radiator fan. You can connect the radiator fan to the car battery with jumper wires to see if the fan runs normally. You can connect a low impedance lamp in series with the motor, turn it through, and see if the lamp ever goes dark, which is the most sensible way.
What controls a car radiator fan?
Mechanical (Belt-driven) Fans: These fans are connected directly to the engine and are driven by a belt. They spin at a speed proportional to the engine's RPM. Electric Fans: These fans are controlled by the ECM (Engine Control Module) based on the information from temperature sensors.
